The invention concerns an X-ray analysis instrument, in particular, an X-ray diffractometer, comprising                an X-ray source that emits an X-ray beam,        an X-ray optics, in particular, a multi-layer X-ray mirror,        and a collimator mechanism, wherein the collimator mechanism forms an aperture window with an aperture opening through which at least part of the X-ray beam passes.        
An X-ray analysis instrument of this type is disclosed e.g. in DE 10 2004 052 350 A1.
X-ray diffractometry is an efficient method for non-destructive chemical analysis of, in particular, crystalline samples. In modern X-ray diffractometers, the X-ray beam that is generated by an X-ray source is directed onto a sample via a multi-layer optics and the diffracted X-ray radiation is analyzed by a detector.
The multi-layer X-ray optics performs monochromatization and mainly shaping of the X-ray beam in an X-ray analysis apparatus with good efficiency. However, the structure of the multi-layer X-ray optics also determines the beam properties on the output side of the multi-layer optics. Physical values such as the input and output convergence, the focal lengths between the source focus and the image focus, the enlargement ratio and thereby also the size of the X-ray beam in the image focus must be determined prior to production of the multi-layer optics. In particular, it is not possible to vary the surface curvature of a multi-layer X-ray mirror or the layer separations in its multi-layers at a later time. For this reason, the multi-layer X-ray optics are basically inflexible.
One particularly important property in X-ray diffractometry is the convergence angle β, since the resolution of a diffractometer decreases with increasing convergence angle. Convergence collimators have been disclosed for adjustment to varying measurement requirements.
U.S. Pat. No. 7,386,097 describes several holes of identical diameter on a rotatably disposed disc of an X-ray analysis device, which generates a collimator function. A collimator can be continuously moved in a first direction through slight rotation of the disc, and a collimator can be moved in discrete steps in a second direction by changing to a different hole on a different radius of the disc. There are different hole sets with different hole diameters. A similar functionality can be obtained with a band having several holes.
U.S. Pat. No. 7,245,699 B2 discloses a Montel optics with a variable collimator that is mounted thereto, comprising two L-shaped collimator sections one of which can be moved along the angle bisector between the two mirror surfaces.
In both cases, the beam conditioning possibilities are limited. The perforated disc of U.S. Pat. No. 7,386,097 only allows stepped adjustment of the beam divergence (in correspondence with the hole diameter of the different hole sets) and also only stepped collimator shift in one direction. Moreover, the mechanical structure is very complex. The collimator mechanism of U.S. Pat. No. 7,245,699 B2 basically always collimates out a part of the X-ray radiation that is remote from the source.
It is the underlying purpose of the present invention to present an X-ray analysis instrument that offers a greater variety of beam conditioning possibilities in order to thereby improve the field of use of multi-layer X-ray optics.